View Full Version : My LASER current meter for DC tubes.

Robert Silvers
10-16-2013, 4:46 PM
I had to go down to 77% power to not exceed the 26mA that RECI says is needed to reach 10,000 hours.


Robert Silvers
10-16-2013, 5:32 PM
Now I can adjust 100% power to be 26 mA.


Dave Sheldrake
10-16-2013, 6:48 PM
From post 18 in the Triumph review thread

China tends to set up machines in many cases by the cutting ability of the tube (output beam power)rather than by testing the actual supplied current, if they get 100 watts of beam that can on occasion mean over driving the tube.(not all of them by any means but some do it)

Looks like China did exactly that on yours Rob, Matched power supplies are essential on Chinese made machines or short tube life becomes the norm.



Larry Robinson
10-16-2013, 7:25 PM
I have mine set to 65% in order to stay under 26 mA.

Dave Sheldrake
10-16-2013, 7:32 PM
What was your original pump current at 100% Larry?



Robert Silvers
10-16-2013, 8:30 PM
I just adjusted the power supply. I could not access the screw without unscrewing the entire power supply. I had to turn it left by 2.5-3 turns.


10% 4.5 mA
20% 7.2 mA
30% 6.5 mA
40% 10 mA
50% 15 mA
60% 20 mA
70% 23.5 mA
80% 26.5 mA
90% 29 mA
98% ~32 mA


10% 4.0 mA
20% 5.5 mA
30% 7.0 mA
40% 7.0 mA
50% 8.5 mA
60% 13.2 mA
70% 18.0 mA
80% 21.5 mA
90% 24.0 mA
98% 26.0 mA

Notice that before 20 and 30% were about the same (actually 30 was less than 20). After 30 and 40% were about the same. So this is not very linear.

In any case, I am happy that I can now run at an indicated 100%, even if it is the same as what used to be 80%.

Robert Silvers
10-16-2013, 9:42 PM

Robert Silvers
10-17-2013, 1:31 AM
I thought about it more and changed it to be 28 mA at 98% (the highest my laser firmware will allow). RECI just says to never run it over 28, so that makes sense to make 28 the max. Now if I set the software to 90%, it will be comfortably at or below 26 mA.

These things should have hour meters in firmware.

Rodne Gold
10-17-2013, 2:44 AM
The shenuis do have hour meters built into their software and board firmware , total time on , total X travel , Y travel and so on.
There is a kinda dichotomy between "hours" and tube longevity
8000 hours at an average of 5 hours a day is 1600 days , around 250 working days a year ... around 6 years...
Will the gas in the tube not have leaked in this time? IE if you had a Reci on the shelf for 7 years - could you expect it to work?
I'm not too sure of that....

Larry Robinson
10-17-2013, 7:55 PM
Dave, Not sure what you mean by "pump current"?

Dave Sheldrake
10-17-2013, 8:26 PM
Dave, Not sure what you mean by "pump current"?

my fault Larry, Lasers are generated when a "Gain" medium is *pumped* either by a DC voltage, an RF signal,a Diode or a Chemical Reaction (leaving out nuclear lasers and other more complex types).

In ours the gas molecules(CO2 molecules) get "excited" by this pumping and barf out a photon before returning to the unpumped state waiting to be hit again so it can pop out another photon.

These Photons are in the form of light hence a laser beam.

In this case it was the pumping current (mA) I was interested in. My fault, sometimes I assume when I shouldn't :)